Neurocognitive sequelae in the treatment of low-grade gliomas

Patients with low-grade gliomas may live without disease progression for many years after initial diagnosis and treatment, but long-term cognitive deficits, which affect up to 90% of patients, can have a sustained negative effect on their daily functioning and quality of life. Cognitive deficits in patients with low-grade gliomas may be caused by the tumor itself or by various other factors including tumor-related epilepsy, tumor treatment (surgery, radiotherapy [RT], medical therapy [including chemotherapy]), psychological stress, or a combination of these. Although some studies suggest a strong link between RT and neurocognitive sequelae, other studies have found little evidence that RT is a major risk factor for cognitive deficits and suggest that other factors may play a major role. The results of a recent cross-sectional study involving 195 patients with low-grade gliomas (104 of whom received RT) strongly suggest that standard focal RT with fractional doses less than 2 Gy is not generally associated with an increased risk of cognitive deficits, but that higher fractional doses are likely to result in cognitive disability. Notably, the presence and severity of epileptic seizures and/or the use of antiepileptic drugs were more strongly associated with cognitive deficits than was RT. This and other studies suggest that disease and treatment factors other than standard focal RT may be more important with respect to increasing the risk of neurocognitive sequelae in patients with low-grade gliomas.